Using TV as monitor via S-video

[Keyser.]

hey all, sorry if this has been posted before.

I want to hook my 42" Samsung HDTV up to my computer so that I can watch cardrunners videos and stuff in my living room. I've got a long enough S-video cable, and both my TV and computer video card have S-video inputs.

I've hooked up the cable to both ends and consulted a few online guides but I'm a little lost. What do I do now? I couldn't find anything in my display properties menu or in my video cards control center program that tells me what to do. any ideas?